SUPPLEMENTARY INFORMATION
PAPER Optical gain in silicon nanostructures P11118
AUTHORS Pavesi, Dal Negro, Mazzoleni, Franzo, Priolo
14000
12000
10000
-1
GAIN (cm )
8000
6000
4000
2000
0
-2000
-4000
550
600
650
700
750
800
850
900
W avelength (nm)
Figure 1. Wavelength dependence of the single pass gain values for the Si nanocrystals
implanted into quartz. The figure shows only a few data points because of the limited
number of wavelengths available to us. The other various experimental details are the
same as those described in the manuscript.
120
80
-1
Gain (cm )
40
0
-40
-80
-120
-160
fit to eq. (1-paper)
with eq. (1-letter)
-200
450 500 550 600 650 700 750 800 850 900 950
Wavelength (nm)
.
Figure 2: (full line) Spectral dependence of the net modal gain derived by using,

1 I
g  ln  2 L  1 (1)
L   IL

where all the symbols have the same meanings as in Ref. [J. D. Thomson et al. Applied
Physics Letters 75 (1999) 2527]. The points refer to the data shown in Fig. 3 of the paper
obtained by fitting the ASE data.
2.0
SiO2/NS(n=1.89)/SiO2/air waveguide
=0.097
SiO2/NS(n=1.71)/SiO2/air waveguide
=0.017
1.8
1.4
1.2
1.0
0.8
refractive index
Electric field (TE0)
1.6
0.6
0.4
0.2
0.0
-3.0
-2.0
-1.0
0.0
1.0
depth (m)
Figure 3: Electric field profile for the fundamental TE mode of a four layers waveguide at
a wavelength of 0.8 μm. The waveguide was formed by a 0.1 μm thick NS layer on top of
a quartz substrate and capped by a 0.06 μm thick SiO2 layer. The external medium was
air. The effective refractive index of the NS implanted region, for the full line plot, was
 M
 eff   M
 f
estimated by using the Maxwell Garnett approximation
, which
 eff  2 M
 f  2 M
is valid for spherical particles of dielectric constant  (here we use  =15.21 as for Si)
embedded in a medium of dielectric constant  M (here we use  M =2.102 as for SiO2)
with a volumetric fraction f=0.28 (corresponding to Si nanocrystals with a diameter of 3
nm and a density of 2x1019 cm-3) and yielded an effective dielectric constant  eff =3.57.
Then n   eff =1.89. For the dotted line, we used an effective refractive index for the
NS layer of 1.71 which was measured by ellipsometry on PE-CVD deposited NS. The
profile of the refractive indexes of the two resulting structures is also shown. The optical
filling factor of the mode is defined as .